Iran’s modern history is replete with examples of the
citizenry seeking to reclaim power from despots. The Pahlavi dynasty, which
ruled between 1925 and 1979, regularly faced popular rebellions, including the
Islamic Revolution of 1979. Once the country’s current clerical rulers made
clear their disdain for democracy, they too were beset by protest movements. The
Islamic Republic’s Western enablers present it as strong and steady, but the
theocracy now resembles the Soviet Union in its dying days.

Once in power, Iran’s Islamists faced open rebellion from
the revolutionary factions that objected to their republic of virtue. This was a
battle waged in the streets as well as in Parliament and the press. The mullahs
proved more ruthless than their liberal and Marxist detractors.

The Iran-Iraq war tranquilized Iran’s domestic politics
in the 1980s, as national energies were focused on a savage foreign invader. In
the 1990s the power struggle resumed. The reform movement, led by disgruntled
members of the intellectual and clerical elite, challenged the regime’s
orthodoxies and even called for making the office of the supreme leader
accountable to the electorate. The reformist interlude ended with the student
rebellion of 1999, when government enforcers bloodied the universities.

Then came the Green Movement in June 2009. A rigged
election to restore Mahmoud Ahmadinejad to the presidency brought millions to
the streets. In a matter of days, the slogans went from “Where is my vote?”
to “Down with dictatorship!” Supreme Leader Ali Khamenei initially seemed
flat-footed, the clerical elite unsure if it could trust the security services.

Eventually the theocracy restored order, but it had already
lost whatever tattered legitimacy it had left. The regime shed the facade of
republicanism, purged itself of unreliable elements, imprisoned its most popular
politicians, and abandoned even the pretense of harmonizing faith and freedom.
The notion of political reform was dead and all talk of human rights was only
that—talk. The Islamic Republic proved it could not reform itself.

Meantime, government reports, the controlled press and even
senior Revolutionary Guard commanders reluctantly confess the truth: Islam is
growing weaker within Iran. Mosques, thinning out for 30 years, are now mostly
empty even on religious holidays. Seminaries have few recruits, and the
government of God has trouble supplying mosques with prayer leaders. Secularism
is on the rise, particularly among the youth, among whom religious observance
has declined precipitously. The regime conducts its ritualistic elections, and
apparatchiks like Hassan Rouhani lead a bloated state drowning in corruption.
The specter of the Green Movement haunts tightly controlled elections, as chants
for the overthrow of the regime often erupt.

The ideologically exhausted theocracy tries to revitalize
itself by imperialism and patronage, much as the Soviet Union did in the 1970s.
Mr. Khamenei stands today as modern Persia’s most successful imperialist, as
he has planted Iran’s flag from the Gulf to the Mediterranean. But imperialism
carries costs, as the Shiite militias Iran arms and local allies it subsidizes
burden its treasury.

The regime depicts its adventures as quests to save Arab
Shiites from Sunni domination and Western machination. Foreign wars have become
an advanced guard of the revolution, according to the late Revolutionary Guard
general Hossein Hamedani, who squelched the Green Movement in Tehran and then
organized the Shiite militias fighting in Syria. “To protect the
accomplishments of the Islamic revolution,” Hamedani proudly asserted, “we
had to intervene” in Syria and Iraq.

At home, the clerical regime established an array of
welfare agencies to dispense benefits to its lower-class constituents. This was
not just about fulfilling a religious obligation. The regime sought to tether
the working poor to the new order. Large foundations expropriated the wealth of
the Pahlavis and tens of thousands of affluent Iranians to provide the poor with
housing and health care. But temptations of power proved too much as the mullahs
and their praetorian guard indulged their taste for luxury. Corruption overtook
charity. Class cleavages today are sharper than under the shah. But this vast
revolutionary patronage offers the regime a lifeline from its economic
incompetence and tyranny. It is this lifeline that aggressive sanctions must
choke off.

There are no inevitabilities in history. Nobody knew when
the Soviet Union’s contradictions would overwhelm the system, and there is no
time stamp on the Islamic Republic’s demise. Jimmy Carter and the vast
majority of the Democratic Party wanted to coexist with the Soviet Union. But
Ronald Reagan helped crack the Soviet Communist Party by waging economic
warfare, empowering dissidents, and shrinking its imperial frontiers.

President Trump should follow Reagan’s example, not Mr.
Carter’s. The U.S. should once more establish contact with and financially
assist dissident organizations in Iran. There is no substitute for presidential
declaration, and Mr. Trump should embrace Reagan’s model of speaking directly
to the Iranian people while castigating their illegitimate regime. Washington
should again impose crippling sanctions to deny the mullahs their patronage
networks, the key to their power. A formula that led to the collapse of the
mighty Soviet empire can surely down Mr. Khamenei’s and the Revolutionary
Guard’s kleptocracy.